1. Field of the Invention
This invention relates to water-cooled furnace covers, which can be attached to cover steel-making or smelting furnaces such as arc furnaces, plasma furnaces, induction furnaces and the like.
2. Description of the Prior Art
Recently, many improvements have been proposed in an effort to extend the service life of the furnace cover.
For example, in a furnace cover formed of fire bricks, even if cooling water is passed through the interior thereof, it is difficult to considerably decrease a degree of wear of the surface thereof.
In order to overcome this, one method has been proposed in which the body portion of the furnace cover is formed of steel material instead of using the fire bricks and to internally cool the steel material. This proposal, however, gives rise to a problem in which radiant heat increases in quantity because the steel material is high in coefficient of heat-transfer.
In view of the above, another proposal has been made in which a layer of oxide film or castable material is applied to a surface of the furnace cover opposite to the interior of the furnace for the purpose of heat insulation. This arrangement suffers, however, from a problem that slags occurring within the furnace during the operation of steel making are scattered so that the slags are adhered to the aforementioned layer and then the slags gradually form into a large mass, and as a consequence, when the massive slag falls by the gravity thereof, the aforesaid insulating layer is forced to be peeled off.